It started with a repetitive click, the sound the actuator in a laptop hard drive makes when it is finding it hard to read important portions of the disk platter. Gradually, the laptop booted more and more slowly, accessed programs less reliably, and took minutes to load simple programs.

Nothing could stop the downward spiral towards hard disk death.

Luckily, Id seen it coming and backed up most of the important data. I was even ready with the emergency OS reinstall disks and a brand new hard disk for when the inevitable day finally arrived.

No matter how well prepared you are for a hard disk crash, if it is the boot drive you have an interesting issue to confront. It only dawned on me as I secured the new drive in the laptop, turned on the PC and prepared for it to boot from the first Windows XP OS re- install disk.

As the laptop was three years old, reinstalling the OS to the state it was when new was only the start of my journey - what about all the updates Microsoft has issued for XP since then?

Any PC of this vintage will have to download and reinstall the major SP2 security overhaul and, it turns out, SP1 updates before you even get to that stage. A number of reboots later, you will then have to add critical patches issued in the year and a bit since SP2 was released. Run Office? There is at least one major patch release (remember the GDI vulnerability?) for that too.

I immediately dusted off my framed picture of Bill Gates, and readied myself to chuck darts at it. It's not necessarily Bill Gates's fault that my hard disk has crashed and is going to be a cow to reinstall, but it makes me feel better to personalise my predicament, however unreasonably. Windows does that to people sometimes.

Four to five hours later Finally, you set about installing all the other bits of security software you might want to run. More reboots. It was like a reliving of recent time in very slow motion. Once SP2 was installed, I had to download a couple of vendor patches for internal systems not compatible with it. Reboot again.

There is now really is no such thing as a definitive operating system or software release, so often are PCs updated. Vista will likely be out-of-date the day after you load it. The interesting things is that most of my experience on XP is down to retrospective security patching, and has little to do with adding features to the software.

Software evolves in real time, and it can only be a matter of time before the process of reinstalling an OS will have become so onerous that it will have to be done using a simple boot disk followed by a remote reinstall.

If this was a small company using fairly standard PCs  perhaps most of which were identical or near identical  it would have been easy to create a more updated reinstall image to simplify this process. But you cant easily do that with a laptop, because each one is subtly and critically different from even a successor from the same manufacturer. You have to start from the point that the operating system worked correctly with the hardware, and that means using the supplied rescue disks that came with the laptop.

One solution  the one I should have bothered with before now  is to create a drive image using one of a number of utilities such as Norton Ghost. This is only as good as the last image made, of course, but it would at least have saved me from reacquainting myself with every patch Microsoft has released in 36 months.